I have a shelving unit made of those wire crate things sitting right beside me.
Not super sturdy, but is sturdy enough leaning up against the wall. That puts the bottom of my box fan on waist level (and serves as a table for my timer (for TTT race starts), spare bottles, gel, Kleenex, whatever). Have to have the fan offset at a bit of an angle so that the fan isn't trying to suck air out of the wall to blow on me (and it's a box fan so it's not as powerful), but it does a decent job. I like that I can just reach over and change the power from low at the start to high later (can set different fan settings as goals - 2nd lap up box hill gets an extra notch on the fan, etc.) Unfortunately, because the airflow is angled and coming at me from 10 o'clock or so (maybe more like 10:30), I really only get max cooling in one position (I have it set for the hoods). Don't get quite as much out of the saddle sprinting and get even less when sitting up off the bars to stretch my back or whatever. If you could set it up to hit you straight on (or have multiple fans to hit you in different riding positions, it'd probably work well.